Measurement of the Thermal Diffusivity of Molten Salts by the Forced Rayleigh Scattering Method (Measurement of molten Alkali metal Chlorides at Temperatures above 1000 °C)

The paper reports measurements of the thermal diffusivity of four molten alkali chlorides (LiCl, NaCl, RbCl and CsCl) in the temperature range above 1000 °C by the forced Rayleigh scattering method. The dye substance employed is KaCoOr in order to color the transparent molten salts. The accuracy is estimated to be ±4 to ±11% depending on the measured substances. In comparison with the present results converted to thermal conductivity, most of the previous experimental data obtained by steady-state methods show larger values (up to about five times) which may be due to the presence of convection and radiation. It is found that the thermal conductivity of these series of molten alkali metal chlorides decreases with increasing molecular weight, and the temperature coefficients are weakly negative.